Last location
iOS 8 will automatically send the last known location of a device to Apple when your battery is low. You can turn this feature off if you think it erodes your privacy, though it's meant to help you find lost devices and is not enabled by default. You’ll find it in Settings>iCloud>Find My iPhone (must be on)> Send Last Location in the Advanced section at the bottom of the list. This means if you drop your device in a local park, you’ve got a chance of finding it - even if it does run out of power.